CBS is delaying production on “The Big Bang Theory” — which was supposed to begin Wednesday — as five main cast members still don’t have contracts.

It’s good to hear they didn’t wait until the last minute.

Jim Parsons, Johnny Galecki, Kaley Cuoco, Simon Helberg and Kunal Nayyar haven’t agreed on contract terms with Warner Bros. Television for the show’s eighth season, according to The Hollywood Reporter.

“Due to ongoing contract negotiations, production on The Big Bang Theory — which was originally scheduled to begin today — has been postponed,” WBTV said, in a statement released Wednesday.

It’s unclear how long the impasse will go on. The work stoppage somehow comes as a surprise to the studio, which expected the cast to arrive back at work Wednesday, with or without a contract, the report said.

Emmy winner Parsons, Galecki and Cuoco are negotiating collectively and reportedly want raises from their current $325,000 per episode up to $1 million, with a cut of the show’s profit.

Note to self: Enroll children in acting classes immediately.

Helberg and Nayyar are negotiating together and also want big raises. Co-stars Mayim Bialik and Melissa Rauch have already received new deals that include nice raises, according to the Reporter.

The contract rift began in September. The show has been renewed for three more seasons, which gives the cast some serious leverage, given that the show has been TV’s No. 1 comedy since the 2010-11 season. The show also does very well in syndication on TBS, with repeats often getting better ratings than original shows on the big four networks.

That’s some serious nerd power, right there.

The cast didn’t show up at last weekend’s Comic-Con in San Diego. Writers for the show filled in. Parsons was there the previous day, but to support DreamWorks Animation’s “Home,” in which he has a voice role.